Balkash, lake, 6,562 sq mi (16,996 sq km), c.350 mi (560 km) long, maximum width c.45 mi (70 km), in E Kazakhstan. The lake, which has an average depth of 20 ft (6 m), stretches from the Kazakh Hills in the northeast to desert steppes in the southwest. The eastern half of the lake is saline; the western half, separated from the eastern section by a sandbar and fed by the Ili River, is fresh. Lake Balkash, which has no outlet, is slowly shrinking from evaporation and reduced inflows from its tributaries. There are valuable copper deposits along the northern shore, and the city of Balkash has a large copper smelter.

Balkash (bäl-käsh´), city (1989 pop. 86,609), in Kazakhstan, on the north shore of Lake Balkash. A railroad terminus and port, it has fish processing and copper-smelting industries. Balkash was founded as Bertys in 1929 and was renamed in 1936.